Hisao Hamaguchi

Discovery of 3,6-dihydroimidazo[4,5-d]pyrrolo[2,3-b]pyridin-2(1H)-one derivatives as novel JAK inhibitors.

Because Janus kinases (JAKs) play a crucial role in cytokine-mediated signal transduction, JAKs are an attractive target for the treatment of organ transplant rejection and autoimmune diseases such as rheumatoid arthritis (RA). To identify JAK inhibitors, we focused on the 1H-pyrrolo[2,3-b]pyridine derivative 3, which exhibited moderate JAK3 and JAK1 inhibitory activities. Optimization of 3 identified the tricyclic imidazo-pyrrolopyridinone derivative 19, which exhibited potent JAK3 and JAK1 inhibitory activities (IC50=1.1 nM, 1.5 nM, respectively) with favorable metabolic stability.

Synthesis and Evaluation of 1H-Pyrrolo[2,3-b]pyridine Derivatives as Novel Immunomodulators Targeting Janus Kinase 3

Janus kinases (JAKs) have been known to play crucial roles in modulating a number of inflammatory and immune mediators. Here, we describe a series of 1H-pyrrolo[2,3-b]pyridine derivatives as novel immunomodulators targeting JAK3 for use in treating immune diseases such as organ transplantation. In the chemical modification of compound 6, the introduction of a carbamoyl group to the C5-position and substitution of a cyclohexylamino group at the C4-position of the 1H-pyrrolo[2,3-b]pyridine ring led to a large increase in JAK3 inhibitory activity. Compound 14c was identified as a potent, moderately selective JAK3 inhibitor, and the immunomodulating effect of 14c on interleukin-2-stimulated T cell proliferation was shown. Docking calculations and WaterMap analysis of the 1H-pyrrolo[2,3-b]pyridine-5-carboxamide derivatives were conducted to confirm the substituent effects on JAK3 inhibitory activity.

Synthesis and evaluation of novel 1H-pyrrolo[2,3-b]pyridine-5-carboxamide derivatives as potent and orally efficacious immunomodulators targeting JAK3.

Janus kinases (JAKs) regulate various inflammatory and immune responses and are targets for the treatment of inflammatory and immune diseases. As a novel class of immunomodulators targeting JAK3, 1H-pyrrolo[2,3-b]pyridine-5-carboxamide derivatives are promising candidates for treating such diseases. In chemical modification of lead compound 2, the substitution of a cycloalkyl ring for an N-cyanopyridylpiperidine in C4-position was effective for increasing JAK3 inhibitory activity. In addition, modulation of physical properties such as molecular lipophilicity and basicity was important for reducing human ether-a-go-go-related gene (hERG) inhibitory activity. Our optimization study gave compound 31, which exhibited potent JAK3 inhibitory activity as well as weak hERG inhibitory activity. In cellular assay, 31 exhibited potent immunomodulating effect on IL-2-stimulated T cell proliferation. In a pharmacokinetic study, good metabolic stability and oral bioavailability of 31 were achieved in rats, dogs, and monkeys. Further, 31 prolonged graft survival in an in vivo rat heterotopic cardiac transplant model.

Novel quinuclidinyl heteroarylcarbamate derivatives as muscarinic receptor antagonists.

Herein, we describe the synthesis and pharmacological profiles of novel quinuclidinyl heteroarylcarbamate derivatives. Among them, the quinuclidin-4-yl thiazolylcarbamate derivative ASP9133 was identified as a promising long-acting muscarinic antagonist (LAMA) showing more selective inhibition of bronchoconstriction against salivation and more rapid onset of action in a rat model than tiotropium bromide.

Discovery and structural characterization of peficitinib (ASP015K) as a novel and potent JAK inhibitor

Janus kinases (JAKs) are considered promising targets for the treatment of autoimmune diseases including rheumatoid arthritis (RA) due to their important role in multiple cytokine receptor signaling pathways. Recently, several JAK inhibitors have been developed for the treatment of RA. Here, we describe the identification of the novel orally bioavailable JAK inhibitor 18, peficitinib (also known as ASP015K), which showed moderate selectivity for JAK3 over JAK1, JAK2, and TYK2 in enzyme assays. Chemical modification at the C4-position of lead compound 5 led to a large increase in JAK inhibitory activity and metabolic stability in liver microsomes. Furthermore, we determined the crystal structures of JAK1, JAK2, JAK3, and TYK2 in a complex with peficitinib, and revealed that the 1H-pyrrolo[2,3-b]pyridine-5-carboxamide scaffold of peficitinib forms triple hydrogen bonds with the hinge region. Interestingly, the binding modes of peficitinib in the ATP-binding pockets differed among JAK1, JAK2, JAK3, and TYK2. WaterMap analysis of the crystal structures suggests that unfavorable water molecules are the likely reason for the difference in orientation of the 1H-pyrrolo[2,3-b]pyridine-5-carboxamide scaffold to the hinge region among JAKs.